There have been two ways to iterate vm_area_struct until Linux 6.0:
1) by rbtree, aka vma.vm_rb;
2) by linked list, aka vma.vm_{next,prev}.
However with the maple tree patches[1][2] in Linux 6.1, vm_rb and
vm_{next,prev} are removed from vm_area_struct. The vm_area_dump()
in crash mainly uses the linked list for vma iteration, which will
not work for this case. So the maple tree iteration needs to be
ported to crash.
For crash, currently it only iteratively reads the maple tree,
no more rcu safe or maple tree modification features needed.
So we only port a subset of kernel maple tree features.
In addition, we need to modify the ported kernel source code,
making it compatible with crash.
This patch deals with the two issues:
1) Poring mt_dump() function and all its dependencies from
kernel source to crash, to enable crash maple tree iteration,
2) adapting the ported code with crash.
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=524e00b36e8c547f5582eef3fb645a8d9fc5e3df
[2]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=763ecb035029f500d7e6dc99acd1ad299b7726a1
Signed-off-by: Tao Liu <ltao@redhat.com>
Tao Liu